Lubricating compositions



Patented Dec. 8, 1953 I LUBRH'JATING COIWPOSITIONS mm. McCarthy, .Allison Park, Pa., assignor to Gulf Research & Development Company, Pittsburgh, Pa., a corporation of, Delaware 1% Drawing. Application June so, 1949,

' Serial No. 102,449

. 1 This invention relates to lubricating compositions and, more particularly, to the class of 14 Claims. (01. 25.2-49.7)

lubricants existing as plastic solids or jellies 1 adapted to the lubrication of wheel bearings, ball or roller bearings in light machinery, pump packing glands, spindles, chassis and universal joints and the like.

. I have discovered that a lubricating composition having the consistency of a grease and having good mechanical and lubricating properties over a wide temperature range can be prepared by dispersin a small amount of a compound of a bentonite and an organic base in an ester of a dibasic acid.

Since many of the properties possessed by the esters are imparted to the lubricating composition, I advantageously employ esters which have a majority of the properties of hydrocarbon oils of lubricating grade such as customarily used in compounding greases. While esters having viscosities as high as 4000 SUS at 100. F. may be used, I prefer to use esters having viscosities of about 45 to about 400 SUS at 100 F. If desired, a mixture of esters of suitable viscosity may be employedinstead of a single ester, by means of which, any desired viscosity within the range of 45 to 4000 SUS at 100 F. may be sea cured. The viscosity of the ester has little effect on the dropping point of the compositions, but more viscous esters produce compositions having greater stickiness and adhesive properties than do the less viscous esters. Ordinarily the more viscous esters are used in producing lubricants of greater consistency. However, the consistency can also be adjusted by the amount of the bentonite compound used. In addition to possessing lubricating properties, the esters should be substantially neutral. Free acids tend to catalyze the oxidation of the esters, resulting in compounds which are corrosive to metals. Therefore, to produce a grease-like lubricant which is stable and which is substantially noncorrosive to metals, I employ esters preferably having a neutralization number below about 0.2;

Exemplary of some of the preferred esters used in making the compositions of the present invention are the esters of aliphatic dibasic acids and alcohols containing at least four aliphatic carbon atoms, preferably between 6 and 16 carbon atoms. Examples of some of the alcohols which can be used are l-butanol; 2-butano1; 2-

methyl-Z-propanol; l-pentanol; 2-pentanol; 2-methyl-2-butanol; l-hexanol; 2-hexanol; 3- hexanol; Z-methyl-l-pentanol; 3-methyl-l-pentanol; 4-methyl-l-pentanol; ,i 2,4-dimethyl-2- 2 pentanol; 2,3-dimethyl-3-pentanol; '2,4-dimethyl-3-pentanol; 3-ethyl-3-pentanol; Z-methyl-lhexanol; fi-methyl-l-hexanol; 2-methyl-2-hexanol 5-methyl-2-hexanol; 3-methyl-3-hexanol; 5-methyl-3-hexanol; l-heptanol; Z-hcptanol; 1- heptanol; 2-methyl-2-heptanol; S-methyl-Z- heptanol; 4-methyl-4-heptanol; Z-ethyl-l-hexanol; 3-ethyl-3-hexanol; 3-ethyl-2-methyl-3- pentanol; l-octanol; 2-octanol; Z-methyl-Z-octanol; 2,6-dimethyl-4-heptanol; 4-ethyl-4-heptanol; 3-ethyl-5-methyl-3-heptanol; 1-nonanol; 2-nonanol; 3-nonanol; -nonanol; 5-nonanol; 2-methyl-l-nonanol; 3,7-dimethyl-l-octanol; 3- ethyl-E-octanol; l-propyll-heptanol; 3-isopropyl-fi-methyl-l-hexanol; 1-decanol; 4-decanol; lauryl alcohol; myristic alcohol; cetyl alcohol; stearyl alcohol; and the like.

As examples of some of the dibasic acids suitable for thepreparation of the esters used in making the compositions of the present invention there may be mentioned oxalic, ma1onic,succini-c, isosuccinic, glutaric, ethyl malonic, pyrotartaric, adipic, pimelic, suberic, azelaic, sebacic, and. phthalic acid. When a low molecular weight acid is esterified a high molecular weight a1- cohol is preferred in order to produce an ester having a majority of the properties of hydrocarbonoils of lubricating grade. While the esters of the aliphatic dibasic acids are preferred, the

esters of aromatic dibasic acids such as the phthalic acid ester of a material such as castor oil or other high molecular weight alcohols may be used. Y

The esters may be prepared by any of the methods known in the art. According to one method, asdescribed in U. S. Patent No. 2,091,241, issued August 24, 1937, a dicarboxylic acid or itsv anhydride is dissolved in an inert solvent, after which the resulting mixture is heated to its boiling point. While maintaining the mixture at its boiling point, an alcohol to give the desired ester is added gradually. When addition of thealcohol is completed, the solvent is distilled off and esterification is carried out at a temperature above 0. According to another suitable method, the alcohol and acid are reacted at an elevated temperature in the presence of a sulfuric acid catalyst. As the reaction proceeds, water is continuously removed by azeotropic distillation with a solvent such as benzene or toluene. When the reaction is substantially complete, the product is washed with dilute alkali to remove any acidic substances. Purification of the product may be accomplished by fractional distillation.

The particular ester employed, as well as the exact amount of the ester, depends upon the characteristics desired in the final lubricating composition. In most instances, however, the ester content comprises about 70 to about 95 per cent by weight of the total composition.

The bentonite compounds employed in accordance with the invention are compounds composed ci a montmorillonite mineral in which at least a part of the cation content of the mineral has been replaced by an organic base. Clays that swell at least to some extent on being contacted with water and contain as a primary constituent a mineral of the group known asmontmorillonites are generally referred to as bentonites. Such clays, which contain exchangeable alkali metal atoms either naturally or after treatment;

magnesium in place of the aluminum content characteristic of the more typical montmorillonites.

The bentonite-organic base compounds are preferably prepared as described in U. S. Patent No. 2,033,856, issued March 10, 1936, by bringing together the bentonite and the organic base in the presence of aqueous mineral acid to efiect base exchange. The organic bases should preferably be titratable with mineral acids. Among these reactive bases are many alkaloids, and cyclic, aliphatic, and heterocyclic amines. The bentonite-organic base compounds used in preparing the lubricating compositions of this invention are preferably those prepared by bringing together a bentonite clay and such organic bases as aliphatic amines, their salts, and quaternary ammonium salts. Examples of such amines and salts are: decylamine, dodecylamine, tetradecylamine, hexadecylamine, octadecylamine, hexadecyl ammonium acetate, octadecyl ammonium acetate, dimethyldidodecyl ammonium acetate, dimethylhexadecyloctadecyl ammonium acetate, dimethyldodecylhexadecyl ammonium acetate, dimethyldicetyl ammonium acetate, dimethyldioctyl ammonium acetate, dimethyldioctadecyl ammonium acetate, and the corresponding chlorides and quaternary ammonium chlorides. The organic bases employed should be such as to impart substantial organophilic properties to the resulting compounds.

The preferred bentonite compounds are prepared from quaternary ammonium compounds in which the N-substituents are aliphatic groups containing at least one alkyl group with a total of at least to 12 carbon atoms. When aliphatic amines are used they preferably contain an alkyl group with a total of at least 10 to 12 carbon atoms.

The amount of the bentonite compound used may vary over wide limits depending upon the particular ester or esters with which the bentonite compound is to be blended and upon the properties desired in the final lubricating composition. While as much as 30 per cent by weight of the total composition may comprise the bentonite compound, I prefer to use smaller amounts, that is, in the order of about 5 to about per cent. In any case, the bentonite compound is dispersed in the ester in an amount suflicient to produce a plastic solid, or composition having the consistency of a grease. -W-hen-a bentonite compound is mentioned, it is understood, of course, that one or more of such compounds are intended.

Lubricating compositions prepared from esters and bentonite-organic base compounds have an advantage over similar compositions prepared from a mineral oil in that inexpensive short or single chain aliphatic amine bentonite compounds can be dispersed in the esters without the use of a solvating agent. Ordinarily the dispersion of short or single chain aliphatic amine bentonite compounds in mineral oils requires the use of one or more solvating agents. I have found, for instance, that a hard greaselike composition can readily be prepared by dispersing octadecyl amine bentonite in di-Z-ethylh'exyl sebacate without using a solvating agent.

When a similar composition was prepared from a mineral lubricating oil and octadecyl amine bentonite, a solvating agent, methanol, was required to aid, in dispersing the bentonite-organic base compound in the oil.

While the compositions produced according to this invention are satisfactory with respect to oxygen stability, it may be desirable in certain instances, as when the composition is subjected to severe operating conditions to incorporate in the composition a small amount of a diaryl amine. As examples of some of the diaryl amines which may be used in the compositions of this invention may be mentioned diphenylamine, phenyl alpha naphthylamine, phenyl beta naphthylamine, alpha alpha, alpha beta, beta beta dinaphthylamines, and the like. Other diaryl amines as well as their derivatives wherein one or more hydrogen atoms on one or both of the aromatic nuclei are replaced by a substituent group may be used. The substituting group may, for example, be one selected from the class of aryl, alkyl, amino, aryloxy and alkyloxy radicals, so long as the presence of the substituent does not render the diaryl amine insoluble in the ester, or soluble in water or otherwise adversely affect the efiectiveness of the diaryl amine. The amount of the diaryl amine employed will depend to a large extent upon the severity of the conditions to which the composition is subjected, as well as the particular diaryl amine used. For instance when the composition is subjected to prolonged use under oxidizing conditions, such as under extreme temperature and pressure, the diaryl amine requirement will be much greater than when relatively mild operating conditions are encountered. Generally, however, the amount of the diaryl amine employed is between about 0.1 and 1.5 per cent by weight based upon the weight of the total composition. In any case, an amount suhicient to substantially inhibit oxidational deterioration is employed.

In order to illustrate the lubricating characteristics of the compositions of the type disclosed herein, a grease-like lubricant was prepared by dispersing 13.0 parts by weight of a dimethyldicetyl ammonium bentonite in 87.0 parts by weight of di-Z-ethylhexyl sebacate. To this dispersion was added 0.5 part by weight of phenyl alpha naphthylamine. The resulting composition was characterized by a highly desirable smoothness and homogeneity of texture. The di-Z-ethylhexyl sebacate had a viscosity of 70 SUS at F., a flash point of 490 1 and a pour point of below -60 F.

Inspection data on the :above composition compare with Army-Navy Specificaticn AN #35. and AN-G- 5a requirements as follows;

i l lv Above com- V Army-Navy requirements 7 position OdorGrease shall have only the odor of the pure Odor of di-Z- liquid component. ethylhexyl sebacate. Corrosion on copper (24 hrs. at 212 F.)Etching or Very slight pitting of the copper strip or green color in the matestain. rial is not permissible. .A slight brown stain on the copper strip shall not be cause for rejection. Dropping point, min, 325 F. 400+ F. Penetration (worked), 260-300 262. High temperature performance (AN- )-Shal1 500 hrs.

lubricate satisfactorily aball bearing for 300 hrs. at 300 F. and 10,000 R. P. M. Water resistanceMax. grease loss permitted20% 0.0% loss.

Low Temperature Torque-A 204K Conrad Type 8 2 sec. and. 3

ball bearing packed with the test grease shall turn sec. its first complete revolution in each direction in not more than 5 seconds at 67 F. Bleeding-Max. loss 5% at end of 30 hours at 212 F. 0.95%. Evaporation-Max. loss 2% after 20 hours at 212 F.. 0. Oxidation-Max. drop in 100 hours5 lbs.

Pounds Adrop- 100 hours 200 hours. 300 hours Working stabilityPenetration of 100,000 strokes shall not exceed 375.

acid.

Lubricating composi- Consistency tion, parts by weight (AS'IM D217-44T) Dimethyl- D1-2-ethylhexyl sebai fig fi Unworked Worked cate bentonite While this invention has been described with reference to specific details and examples of the production and properties of the composition of my invention, it is to be understood that the invention is not intended to be limited to such details and examples, except as recited hereinafter in the appended claims.

I claim:

1. A lubricating composition consisting essen tially of a dispersion of a compound of a bentonite and an organic nitrogen base in a major amount of an ester of an aliphatic dibasic acid, said ester having a majority of the properties of a hydrocarbon oil of lubricating grade, wherein said bentonite compound is dispersed in said ester in an amount sufiicient to produce a composition having the consistency of a grease.

2. A lubricating composition consisting essentially of a dispersion of a compound of a bentonite and an organic nitrogen base in a major amount of an ester of a dibasic acid, said ester having a majority of the properties of a hydrocarbon oil of lubricating grade, wherein said bentonite compound is dispersed in said ester in an amount sufficient to produce a composition having the consistency of a grease.

3. A lubricating composition consisting essentially of a dispersion of a compound of a bentonite and an organic nitrogen base in a major amount of an ester of an aliphatic dibasic acid, said ester having a viscosity between about 45 and 4000 SUS at F., wherein said bentonite compoundis dispersed in said ester in an amount sufficient to produce 'a composition having the consistency'of a grease.

4.-A lubricating composition consisting essentially of a dispersion of a compound of a bentonite and an organic nitrogen base in a major amount of an ester of an aliphatic dibasic acid and an alcohol containing at least 4.- aliphatic carbon atoms, wherein said bentonite compound 5. A lubricating composition consisting essen tially of a dispersion of a compound of a hentonite and an organic nitrogen base in a major amount of an ester of an aliphatic dibasic acid and an alcohol containing at least 4 aliphatic carbon atoms, said ester having a viscosity between about 45 and about 4000 SUS at 100 F., wherein said bentonite compound is dispersed in said ester in an amount suificient to produce a compositionhaving the consistency of a grease.

6. A lubricating composition consisting essentially of a dispersion of a compound of a bentonite and an organic nitrogen base in a major amount of an ester of an aliphatic dibasic acid and an aliphatic" alcohol containing between 6 and 16 carbon atoms, wherein said bentonite compound is dispersed in said ester in an amount sufilcient to produce a composition having the consistency of a grease.

'7. A lubricating composition consisting essentially of a dispersion of a compound of a bentonite and an organic nitrogen base in an ester of an aliphatic dibasic acid and an aliphatic alcohol containing between 6 and 16 carbon atoms, said ester having a viscosity between about 45 and about 4000 SUS at 100 F,. wherein said bentonite compound is dispersed in said ester in an amount sufficient to produce a composition having the consistency of a grease.

8. A lubricating composition consisting essentially of a dispersion of a compound of a bentonite and an organic nitrogen base in an ester of an aliphatic dibasic acid and an aliphatic alcohol containing between 6 and 16 carbon atoms, said ester having a viscosity between about 45 and about 4000 SUS at 100 F., wherein said bentonite compound is dispersed in said ester in an amount corresponding to about 5 to about 20 per cent by weight of the lubricating composition.

9. A lubricating composition consisting essentially of a dispersion of dimethyldicetyl ammonium bentonite in di-2-ethylhexyl sebacate wherein said bentonite compound is dispersed in said di-Z-ethylhexyl sebacate in an amount corresponding to about 5 to about 20 per cent by weight of the lubricating composition.

10. A lubricating composition consisting essentially of a dispersion of octadecyl amine bentonite in di-Z-ethylhexyl sebacate, wherein said octadecyl amine bentonite is dispersed in said di-Z-ethylhexyl sebacate in an amount sufiicient to produce a composition having the consistency of a grease.

11. A lubricating composition consisting essentially of a dispersion of dimethyldicetyl ammonium bentonite in di-2-ethylhexyl sebacate, wherein said dimethyldicetyl ammonium bentonite is dispersed in. said diez ethylhexyl tith at i n me n sum ient: ta. pro uce a (20111: position having the consietency Qt a te set 12.. A lubricatin compesitien tonsi t ng t a unimrm mixture of a compound of a bentonite nd an or ani n trogen base. at maj am unt of n. es er f n aliphatic dibasic acid n a diaryl amine, wherein said bentqnite eompqunci dispersed in said. ester in an amount eufilc en to. produce a cemposition having the een istency of a. grease and wherein said. di l-l'yl am ne i5 present in an amount sufiieient to gtabilizg the lubricat ng omp sit on against: oxicla iqnel d.e. terioration- 13. A lubricatin comnqsitiqn consittine t a. uniform mixture of about. 0 m abqut 5 pants M weight of di-Z-ethylhexyl sebacate, abq t 5 t9 aheut 30 parts by weight 0t qimethtld eetyl am- References. Cited in the file of this patent UNITED STATES PATENTS Number Name Date 2,248,636 Marsden -2 July 8, 194,1 2,450,221 Asburn Sept. 28, 1948 2,491,054 Morway Dec. 13, 1949 2,531,440 Jordan Nov. 28, 1950 2,554,222 Stross May 22, i951 

1. A LUBRICATING COMPOSITION CONSISTING ESSENTIALLLY OF A DISPERSION OF A COMPOUND OF A BENTONITE AND AN ORGANIC NITROGEN BASE IN A MAJOR AMOUNT OF AN ESTER OF AN ALIPHATIC DIBASIC ACID, SAID ESTER HAVING A MAJORITY OF THE PROPERTIES OF A HYDROCARBON OIL OF LUBRICATING GRADE, WHEREIN SAID BENTONITE COMPOUND IS DISPERSED IN SAID ESTER IN AN AMOUNT SUFFICIENT TO PRODUCE A COMPOSITION HAVING THE CONSISTENCY OF A GREASE. 